While scouring my bookshelves and trawling the internet for a fresh angle on “Casablanca” (1942), director Michael Curtiz’s film about love and sacrifice in wartime Morocco, I came across something old and, if not something new, then something that flew under the radar.

Did you know that there was a sequel to and a remake of “Casablanca,” albeit that one was never made and the other was unofficial? Sequels aren’t, by definition, disheartening. There are enough of them that shine — “Bride of Frankenstein” (1935), “Star Trek II: The Wrath of Khan” (1982), “Toy Story 3” (2010), and, if you insist, “The Godfather: Part II” (1974) — to make a strong case for the defense. But have you ever heard of “Brazzaville”? 

On February 19, 1943, a syndicated entertainment writer, Virginia Vale, wrote that “‘Casablanca’ has scored such a hit that there’ll be a sequel.” Humphrey Bogart and Sydney Greenstreet would be returning, our intrepid reporter announced, “and it’s likely that Geraldine Fitzgerald will have an important role.” 

A treatment was written by Frederick Stephani, the writer and director of “Flash Gordon” (1936). His story divulged the truth about Rick Blaine and Captain Renault: They were Allied spies who had been working in tandem all along. The higher-ups at Warner Brothers, not thinking much of this scenario, quashed the project. Sometimes corporate overlords operate on the side of the angels.

As for a remake: Why bother? For every quality remake — “Nightmare Alley” (2021), say, or “The Wizard of Oz” (1939) — there are any number of films in which time, money, and talent have been squandered. The Coen Brothers’ smugly configured “The Ladykillers” (2004) is one example; Gus Van Sant’s execrable “Psycho” (1998) another.

Still, there was “Passage to Marseille” (1944), a film that reunited Curtiz with a good chunk of the original cast — including Humphrey Bogart, Claude Rains, Peter Lorre, and Sydney Greenstreet — as well as “To Have and Have Not” (1944), in which director Howard Hawks made a conscious decision to massage the Ernest Hemingway novel into a kind of “Casablanca II.”

“To Have and Have Not” is a fine picture, not only because of the chemistry between Bogart and Lauren Bacall, but also due to the songful ministrations of Hoagy Carmichael sitting in for Dooley Wilson at the keyboards. Yet it’s no “Casablanca,” and neither was “Casablanca”  (1983) the television series. 

Don’t remember it? Don’t worry: The five-episode prequel was pulled after the third show due to disastrous ratings. David Soul of “Starsky and Hutch” played Rick, Hector Elizondo was Captain Renault, and Scatman Crothers tinkled the ivories as Sam. These actors couldn’t have been surprised by the show’s failure; they knew they were attempting something close to impossible.

The IFC Center is hosting a run of the one-and-only “Casablanca” directly after the Christmas holiday. It can’t have been a coincidence that this revival comes on the heels of the theater’s presentation of “Alphaville” (1965), a restored version of Jean Luc-Godard’s near masterpiece in which Eddie Constantine wanders through a dystopian future as an unapologetic homage to Bogey himself. Godard had made plain his adoration for Bogart in “Breathless” (1960), in which Jean Paul-Belmondo’s character consciously and continually apes the Hollywood icon. Even as Godard was upsetting the conventions of cinema, he couldn’t bring himself to step on Bogart’s toes.

If it’s been a while since you’ve watched “Casablanca,” be advised: It’s probably not as good as you remember. It’s better. Like all great works of art, the story of Rick, Ilsa, and “As Time Goes By” is a constantly unfolding artifact, a rich and witty entertainment that deepens with renewed contact.

Not everyone agrees. Rotten Tomatoes, the online aggregator of critical opinion, cites that “Casablanca” has a near unanimous approval rating. In the spirit of the holiday season and in the hopes instilled by the coming of a new year, let’s extend our good tidings to that 1 percent whose souls remain unmoved by this supernal film. Someday they, too, shall recognize that a hill of beans is a significant measure of human accomplishment.